An electronic device that stores, retrieves, and processes data, and can be programmed with instructions. A computer is composed of hardware and software, and can exist in a variety of sizes and configurations. What is a Computer
GENERATIONS OF COMPUTERS VCD,DVD,HDD IC WITH PARALLEL PROCESSING PRESENT AND BEYOND NO AI FLOPPY,HDD,CD IC WITH VLSI 1971-PRESENT COMPLICATED FLOPPIES IC 1963-1971 MAINTAINENCE, LESS MEMORY MAGNETIC DISK TRANSISTORS 1956-1963 LARGE IN SIZE, MAINTAINENCE, SLOW PUNCHED CARDS VACCUM TUBES 1945-1956 DISADVANTAGES STORAGE PROCESSING PERIOD
CLASSIFICATION OF COMPUTERS SINCE 1944 MODERNAGE 1890-1944 MIDDLEAGE 5000B.C-1890 A.D DARKAGE
MIDDLE AGE MODERN AGE HOLLERITHS TABULATING MACHINE ATANASOFT BERRY COMPUTER MARK1 1944 ENIAC
TYPES OF LANGUAGES MACHINE LEVEL LANGUAGE ASSEMBLY LEVEL LANGUAGE HIGH LEVEL LANGUAGE SOFTWARE SYSTEM SOFTWARE APPLICATION SOFTWARE
INVENTORS RAY TOMLINSON E-MAIL TIM BERNER LEE WWW 1960 MINICOMPUTER TED HOFF MICROPROCESSOR DOUG ENGELBART MOUSE
An electronic device that stores, retrieves, and processes data, and can be programmed with instructions. A computer is composed of hardware and software, and can exist in a variety of sizes and configurations. What is a Computer Hardware & Software The term hardware refers to the physical components of your computer such as the system unit, mouse, keyboard, monitor etc. The software is the instructions that makes the computer work. Software is held either on your computers hard disk, CD-ROM, DVD or on a diskette (floppy disk) and is loaded (i.e. copied) from the disk into the computers RAM (Random Access Memory), as and when required
Types of Computers Mini and Mainframe Computers Very powerful, used by large organisations such an banks to control the entire business operation. Very expensive! Personal Computers Cheap and easy to use. Often used as stand-alone computers or in a network. May be connected to large mainframe computers within big companies.
Hardware Components Input Devices -- "How to tell it what to do“ - A keyboard and mouse are the standard way to interact with the computer. Other devices include joysticks and game pads used primarily for games. Output Devices -- "How it shows you what it is doing" - The monitor (the screen) is how the computer sends information back to you. A printer is also an output device.
Memory –”How the processor stores and uses immediate data” Main Parts of Computer
RAM - Random Access Memory
The main 'working' memory used by the computer.
When the operating system loads from disk when you
first switch on the computer, it is copied into RAM.
Data and programs stored in RAM are volatile (i.e. the information
is lost when you switch off the computer).
ROM – Read Only Memory
Read Only Memory (ROM) as the name suggests is a special type of memory chip that holds software that can be read but not written to.
A good example is the ROM-BIOS chip, which contains read-only software.
Often network cards and video cards also contain ROM chips
How Computer Memory Is Measured Bit All computers work on a binary numbering system, i.e. they process data in one's or zero's. This 1 or 0 level of storage is called a bit. Byte A byte consists of eight bits. Kilobyte A kilobyte (KB) consists of 1024 bytes. Megabyte A megabyte (MB) consists of 1024 kilobytes. Gigabyte A gigabyte (GB) consists of 1024 megabytes .
Microprocessors -- "The brain of the computer“
PCs primarily use microprocessors (sometimes called the chip). The older Intel versions include the 386, 486 and now the Pentium line.
The CPU (Central Processing Unit) is normally an Intel Pentium (or equivalent) and it is one of the most important components within your computer.
It determines how fast your computer will run and is measured by its MHz speed.
Thus a 600 MHz Pentium is much faster than say a 400 MHz Pentium CPU.
It is the CPU that performs all the calculations within the computer.
Software Component Operating systems software The operating system is a special type of program that loads automatically when you start your computer. The link between the hardware and the user Applications software Word processing applications Multimedia applications Database